1. Field of the Invention
The invention relates to a device for facilitating sheet separation or singling, more particularly, in an upper region of a feeder pile, wherein equipment for acting upon an edge of the feeder pile facing away from a processing machine are provided on a supporting structure, the equipment being movable into engagement with lateral edges of the sheet pile.
Published German Patent Document DE 36 19 676 Al discloses a separating device for a multi-layer pile formed of layers of sheets. A leafing device for leafing through the layers of sheets from top to bottom and for detecting the location of cardboard sheets separating individual bundles of sheet layers is assigned to a corner of a multi-layer pile. The sheet layers disposed above a respective determined separating location are lifted so that separating heads may move into the opened separating location, and thus move out respective separated partial quantities of layers of the multi-layer pile from a superimposed congruent location thereof.
The separating device is located at the trailing edge of a multi-layer pile. Although the separating heads are movable in a horizontal plane, they cannot be moved away entirely from the pile. This applies as well to the leafing device which is disposed in a stationary position at a corner of a pile and only scans or tracks in a vertical direction. This requires that the pile be refilled from below, which calls for specific constructional prerequisites which cannot always be provided.
Published German Patent Document 37 06 747 Al discloses a device for automatically infeeding paper layers into a processing machine. Within a supporting structure mounted fixed in position, two carriages are movable on two rack-and-pinion or gear-rack guides. The carriages carry two spindles holding two separating units which are connected to one another and are movable on the spindles. Each of the separating units includes separating means, a retainer or hold-down bar, and a sliding element which, in turn, are fastened to four-bar transmissions. Furthermore, respectively, a pressure roller and a separating blade are arranged on the separating units to enable the separation of individual partial quantities of layers in an upper region of the pile of sheet layers.
With this heretofore known device, it is not possible to facilitate the separation of sheets on a feeder pile and to continuously supply the printing material to a further processing machine, because the pile region is surrounded by a stationary supporting structure, and it is time-consuming and difficult to reach the pile region from the outside for the purpose of refilling the pile from above or from a side, for example.
With feeders of small sheet-fed rotary printing presses, new sheets are replenished on a feed board as soon as the feeder pile has decreased. Heretofore, in the case of a format change, each of the individual elements making-ready or preparing the alignment of the upper region of the feeder pile had to be moved away individually from the pile region and even disassembled therefrom in order to gain direct access to the pile. Only then, could the new sheets be stacked easily and quickly. If the replenished piled sheets are of a different sheet size or format, each aligning element has to be adjusted so as to match or be accommodated to the changed format, which has heretofore resulted in rather lengthy make-ready time periods. Furthermore, it has become apparent that, under certain circumstances, the sheets are not loosened up all the way to the respective trailing edge of the upper region of the feeder pile nor does air blown underneath the upper region of the feeder pile extend to the trailing edge thereof. In fact, the upper sheets of a light printing material have been completely blown off the surface of the pile if too much blowing air is supplied. Furthermore, it has become desirable to protect prestacked copies of small sheet sizes or formats against impacts and the like in order to leave them in the prestacked position, if possible, and to avoid a renewed pile preparation.
Proceeding from the state of the art as outlined above and from the inadequacies of the prior attempts to find a solution for the problem, it is an object of the invention of the instant application to provide a device for facilitating sheet separation or singling with which accessibility of a feeder-pile region and ability to effect format adjustments quickly are considerably improved over the state of the art.